Dissertation / PhD Thesis/Book

PreJuSER-29617

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Funktionelle Analyse des essentiellen Zweikomponenten-Signaltransduktionssystems CgtSR4 aus Corynebacterium glutamicum

Wessel, M. (Corresponding author)FZJ*

2004
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/103

Report No.: Juel-4129

Abstract: Corynebacterium glutamicum is an aerobic gram-positive soil bacterium used for large scale production of amino acids, mainly L-glutamate and L-lysine. Genome sequence analysis revealed the presence of 13 two-component regulatory systems. In this thesis, one of these systems, composed of the sensor kinase CgtS$_{4}$ and the response regulator CgtR$_{4}$, was characterized in order to get information about its function. The following results were obtained: 1. Hydrophobicity plots indicated that the N-terminus (amino acids 4-21) ofthe sensor kinase CgtS$_{4}$ is very hydrophobic and possibly forms a transmembrane helix. A second region of lower hydrophobicity (amino acids 43-63) has a strongly amphiphilic character and might form a membrane-associated helix. Using peptide antibodies it was confirmed that CgtS$_{4}$ is located in the membrane fraction of C. glutamicum cells. 2. The characteristic features of two-component systems could be demonstrated in vitro for CgtS$_{4}$/CgtR$_{4}$ : CgtS$_{4}$ purified by means of a carboxyterminal His- or Strep-tag showed autokinase activity and transferred the y-phosphoryl group of ATP rapidly to the purified response regulator CgtR$_{4}$. 3. A deletion of the cgtSR$_{4}$ genes from the chromosome was only possible in the presence of plasmid-borne functional cgtSR$_{4}$ or cgtR$_{4}$. The conclusion derived from these results that cgtR$_{4}$ but not cgtS$_{4}$ is essential for C. glutamicum could be confirmed by the successful deletion of the chromosomal cgtS$_{4}$ gene. The fact that a deletion of the chromosomal cgtSR$_{4}$ genes was possible in the presence of a plasmid-encoded CgtR$_{4}$ protein with an D52N exchange led to the conclusion that CgtR$_{4}$ is active in its unphosphorylated state. 4. The genes cgtSR$_{4}$ are located directly downstream ofthe pgm gene encoding the glycolysis enzyme phosphoglycerate mutase, indicating that pgm expression might be regulated by the CgtS$_{4}$/CgtR$_{4}$ system. However, transcriptome analyses failed to reveal such a regulation. 5. Genome-wide transcriptome analyses using DNA microarrays indicated that CgtSR$_{4}$ is involved in the response to two different types of stress, i.e. phosphate starvation and oxidative stress. Possibly, CgtS$_{4}$/CgtR$_{4}$ functions as a global regulatory system in different stress situations or even triggers a general stress response. So far, no direct target gene of the response regulator CgtR$_{4}$ could be identified.

Note: Record converted from VDB: 12.11.2012
Note: Düsseldorf, Univ., Diss., 2003

---

Contributing Institute(s):

1. Biotechnologie 1 (IBT-1)

Research Program(s):

1. Biotechnologie (L02)

Appears in the scientific report 2004

---

Database coverage:

---